The present invention generally relates to an automatic call distribution system, and particularly to an automatic call distribution system capable of equally distributing incoming calls which terminate at a pilot extension provided in a private branch exchange, to agent extensions accommodated therein.
An automatic call distribution system is known in a system which equally distributes a number of incoming calls which terminate at a pilot extension provided in a private branch exchange, to agent extensions accommodated therein, so that call traffic is handled effectively and efficiently. A seat booking system for trains and airplanes is an application of the automatic call distribution system.
In a conventional call distribution system, when an automatic call distribution call (hereinafter simply referred to as an ACD call) terminates at a pilot extension which functions as a telephone number representative of a plurality of agents accommodated in a private branch exchange, the system automatically searches a first agent group for an idle agent (available agent). Generally, a plurality of agents are grouped. It is now assumed that two agent groups consisting of first and second agent groups are provided in the system. If the system finds an idle agent in the first agent group, the system connects the ACD call to the found idle agent. On the other hand, if the system cannot find any idle agent in the first agent group, the system couples the ACD call with an announcement machine. Thereby, the caller is provided with an appropriate announcement. Then, the system continues to search the first agent group for an idle agent. When the system finds no idle agent even after the lapse of a predetermined time, the system decides that the search is incomplete (a time out) and provides the caller with another announcement. It is noted that the above-mentioned announcements aim to let the caller know that the connection is being maintained and to reduce a number of intentional midway abandonments of ACD calls by the caller. Then, the system starts to seek an idle agent in the second agent group by referring to a route table which is permitted to be accessed only when the system can find no idle agent in the first agent group even after the lapse of the predetermined time.
In call distribution systems as described above, it is desired that the number of spontaneous midway abandonments be as small as possible, and that many ACD calls can be handled effectively and efficiently with a small number of agents. The above depends on users' requirements. Therefore, it is specifically required to arbitrarily design and modify the routing of ACD calls to the announcement machine and agents.
However, conventional call distribution systems have the following disadvantages. When an ACD call terminates at the above-mentioned pilot extension, the system automatically seeks an idle agent by searching the first agent group. It is to be noted that it is easy to design and construct the system so as to automatically search, without exception, the first agent group for an idle agent when an ACD call terminates at the pilot extension. However, such a procedure cannot satisfy a variety of users, needs. In other words, users desire that easy modification of routing of ACD calls be available. Even if users wish to modify the searching procedure in the conventional systems, it is actually difficult for the users to modify a related system program made by a manufacturer in accordance with any conventionally proposed procedure. From the above viewpoint, it may be said that the system is less flexible. Secondly, two different control procedures are required to seek an idle agent. That is, first, an idle agent in the first agent group is sought, and secondly, an idle agent in the second agent group is sought by referring to the route table when no idle agent can be found in the first agent group even after the predetermined time passes.